| Name | Other Name | Family | Nativ Name | ISO6391 Code | ISO6392T Code | ISO6392B Code | ISO6393 Code | Notes |
|---|---|---|---|---|---|---|---|---|
| Sardinian | Indo-European | sardu | sc | srd | srd | srd + 4 | macrolanguage | |
| Sanskrit | Indo-European | संस्कृतम् | sa | san | san | san | ancient; still spoken; also known as Saṃskṛta | |
| Russian | Indo-European | русский | ru | rus | rus | rus | ||
| Sinhala | Sinhalese | Indo-European | සිංහල | si | sin | sin | sin | |
| Yiddish | Indo-European | ייִדיש | yi | yid | yid | yid + 2 | macrolanguage. Changed in 1989 from original ISO 639:1988; ji. | |
| Western Frisian | Indo-European | Frysk | fy | fry | fry | fry | also known as Frisian | |
| Welsh | Indo-European | Cymraeg | cy | cym | wel | cym | ||
| Walloon | Indo-European | Walon | wa | wln | wln | wln | ||
| Urdu | Indo-European | اردو | ur | urd | urd | urd | ||
| Ukrainian | Indo-European | Українська | uk | ukr | ukr | ukr |